Filter system assembly



Apl 13, 1965 c.JAcuzz1 3,178,024

FILTER SYSTEM ASSEMBLY Filed June 13. 1960 4 Sheets-Sheet 1 AND/O JA GUZZI @Vaga/@MU HIS ATTORNEYS PI'l 13, l1965i c. .lAcUzzl 3,178,024 w FILTER SYSTEM ASSEMBLY Filed June 13, 1960 4 Sheets-Sheet 2 INVENTOR. GANO/00 JA GUZZI H/S ATTORNEYS Apri 13, 1965 c. .JAcUzzl 3,178,024

FILTER SYSTEM ASSEMBLY Filed June 13. 1960 4 Sheets-Sheet .3

IN1/ENT 0411/0/00 JAG Z/ April 13, 1965 c. JAcuzzl 3,178,024

FELTER SYSTEM ASSEMBLY Filed June 13, 1960 4 Sheets-Sheet 4 mm'rox; GANO/00 JA GUZZI BY m 9 /ma/ HIS ATTORNEYS United States Patent Utilice resented ps. i3, 1535 3,178,024 FELTRE SY TEM ASSEMEELY Candido Jacuzzi, Lafayette, Callie, assigner to .lacuzzi ros., Incorporated, a corporation of California Filed .lune i3, i969, Ser. No. 35,58)

4 Claims. (Cl. 2102S3) My invention relates to filters and more particularly to a filter system assembly adaptable for use with swimming pools and the lilze.

The construction of swimming pools is normally accompanied by the installation of a filter system for servicing the pool and maintaining the pool water filtered and clean. Such system includes a filter, a motor for pumping water from the pool through the filter, and a multiway valve assembly for effecting various system combination connections for accomplishing'different1 objectives such as iiltering, backwashing of the filter, land y,by-passing the filter to pump Water directly from the pool into a drain or sewer system. g

Among the objects'of my invention aret.

(l) To providel a novel and improved filter system assembly; i ""f i (2v) To providenovel and improvedililteif'system"astern assembly of the presentinvention;y l I FIG. 2' is a view inv section through apump-valve unit assembly constituting an important' aspectjofthe filter system assembly ofjFlG'. l; "Q FIG. 3 is a view inVV section taken in the plane Sflf of FIG. 2; y Y i' FIG. 4 is a plan view ofthe pump unit assembly'of FIG. 2, with parts removed to eXp-ose interior structure; FIGS. 5-9 are views depicting various'ow `combinations capable of being accomplished by a multiaway valve assembly employed in the system; V I

FIG. lO is a plan view of a multiple filter assembly incorporating the present invention; and

FIG. l1 is a view in elevation of the multiple filter K assembly of FIG. 10.

Referring to the drawings for details of my invention in its preferred form, the filter system assembly 1 may be considered as involving two main sub-assemblies, (1) a tank assembly 3 and (2) a pump-valve unit assembly 5. t

The tank assembly involves a tanl; 7 having an opening 9 0f the manhole type in the upper end thereof, a concave bottom l and legs l, a.; a convex, false, preferably perforated bottom i5, ad pled to support lter material while permitting liquid flow thereby, the perforated false bottom forming a chamber i7 with the tank bottom El. A pipe i3 passes through the false bottom and is welded thereto, with its lower end in the chamber 17 and its upper end terminating preferably io flange E.

In accordance with conventional practice, the filter material may comprise a plurality of layers 21,23, 25, 5:7, etc. of gravel and sand built upon the false bottom l5 with the average particle size of the layers gradually decreasing toward the upper layer.

The opening 9 in the upper end or" the tank is bounded by a horizontal flange 3l having a plurality of threaded bolt receiving recesses uniformly spaced therearound to provide for the mounting and installation of the pumpvalve unit assembly 5.

Such pump-valve unit assembly includes a pump housing 35, having a front wall 36, a rear wall 37 and an upper extension 3S to the rear, the upper end of the housing being planar to provide for the mounting of a multiway valve assembly 4l.

`Within the housingis a pump chamber 43, the input to which is defined by a passageway leading from a threaded inlet opening 47 inthe front wall 36 of the housing, and terminating at a suction opening 51 in the pump chamber, the passageway being enlarned intermediate the two openings to provide a compartment or pocket 53 having an opening 55 `to atmosphere, to permit for the insertion f' a screen basket 57, Thislscreen basket will serveto trap and. remove roni'any inflowing water, debris which may enter with the water and thus prevent the same from gaining accesrsuto the, pump chamber.v v j yA.cover",61.'applifed'" o ver the opening 55 is held in place by `a pressure screw 63, passing through a yoke 65 which stradldles s e eoverand is removablyanchored to lateral K fr r rmxs preferably designed to provide ahousingf'ilvfo'r a purnp rotor 75 driven by a motor 77 mountedgainsttheirear wall of the pump chamber belowl therearvvard ex'tensionSS. l p I 'Within the area covered by the multi-way valve assen bly/1,1 iisi anopening'SS marking the-termination of'a discharge passageway from the pump, including a chamber 87.

The pump i s preferably of the impeller type, in which case the Vrotor will constitute an impeller and the rotor housing'will define a volute' discharging into the chamberS'7,., f v t Extending through the housing independently of the pump chamber and' discharge passageway/are a pair of passageways 91, 93 each terminating at one end in the bottom wall of the housing, and at its other end in an opening 95, 97 respectively in the top planar wall within the area coveredA by the valve assembly l. The lower end ofthe one passageway 9i is preferably threaded for coupling'thereto, a diffuser nozzle 99 in the form of a short closed ended pipe section having a plurality of slits itl-t9 in the cylindrical wall thereof.

Also extending through the housing independently of the pump chamber is another pair of passagcways in the form of chambers 101, 193 each terminating at one end in a preferably threaded opening 65, 1&7 respectively, facing laterally of the housing, while at its other end, each passageway terminates in an opening 199, 111 respectively in the upper planar wall within the area of the multi-way valve assembly 4l.

The terminal openings S5, 95, 97, 16% and lll in the upper planar wall are preferably arranged in a circle M cooperation with the multi-way valve assembly to 5t various combination arrangements between tbe arranca end 85 of the pump discharge passageway and the remaining passageway openings in the upper Wall.

The multi-way valve assembly 41 may comprise a housing in the form of a iianged cover 115 affixed to the upper end wall by cap screws 117 through the flange thereof, the cover being preferably sealed to the upper end wall by an intermediate sealing layer 118 having cut-outs matching the openings 85, 95, 97, 109 and 111.

Centrally of the area spanned by the cover 115, the planar wall is recessed to frictionally receive a shaft pin 119, such pin being preferaby forced or driven into position to preclude rotation thereof.

The cover defines with the upper end wall, a valve chamber 121 in which is rotatably positioned for adjustment, a valve or port body 123, the purpose of which is to provide for selectively coupling the various passageways leading to and from the valve assembly.

The valve or port body is a generall hollow open ended body 125 having an integral central shaft 127 terminating at one end in the plane of the open end of the port body and at its other end, extending beyond said body. The port body is installed in the housing with its open end facing the upper end Wall of the pump housing 35 and preferably in contact with a 4layer of sealing material set into the upper end Wall.

The lower end of the shaft 127 is recessed to slidably fit over the exposed end of the shaft pin 119 while the extending end of the shaft passes through an O-ring seal 131 in the cover 115.

The port body is recessed about its shaft 127 to receive one end of a compression spring 135 disposed under compression, -between the port body 123 and the cover Y115, such spring serving to maintain the port body in pressure sealing engagement with the sealing layer 118. The specific configuration and construction of the port body is controlled by the various connecting functions which it is intended to perform, such functions being accomplished by a combination of integral hole cover sections and partition walls `incorporated into the body structure.

In the specific multi-Way valve assembly depicted in the drawings, a partition Wall formed of two radial sections 141, 143 is adapted, in one position, to span an angle sufiicient to encompass a pair of the openings in the upper end wall, while intermediate the radial sections, in an area not occupied by such openings, is a cover section 145. This partition wall and cover section define a corridor or passageway 147 capable of interconnecting a pair of openings, while the cover section 145 occupies a space between such openings (FIG. 6). With the cover section shifted to a position blocking an opening (FIG. the passageway 147, performs no connecting function, in the specific form illustrated.

A second partition wall extending across the port body and including an intermediate semi-circular section 151 terminating in a radial section 153, 155 at each end respectively defines with the first partition wall, a corridor or passageway 159 of sulicient Width at each end to enable it to simultaneously expose a pair of openings, when the port body is properly positioned to bring this passageway into registry with such openings (FIG. 5).

Integral with this second partion wall and located adjacent one of the radial sections thereof, is a cover section 163 adapted, like the cover section 145, to cover and block an opening when positioned over such opening.

Bounded by the second partition Wall, the cover section 163, and the rim of the port body, is an arcuate area spanning in excess of two openings, thus defining an arcuate compartment 164.

With the port body in the position'of adjustment depicted in FIG. 5, the opening 85 from the discharge passageway of the pump will be blocked off, thus cutting off ow in the system.

Rotation of the port body in clockwise direction to its first operational position as depicted in FIG. 6, will effect a flow connection from the pump discharge passageway opening to the opening 9S leading to one of the passageways 91 leading down to the filter, while leaving the other opening 97 associated with the passageway 93 to the filter open for return flow from the filter. From the opening 97, a iiow connection is established to opening 111 leading down to the lateral passageway 103.

In its next positional adjustment, as illustrated in FIG. 7 the pump discharge passageway will be ow connested directry through corridor 159 the liow passageway 191 leading out of the housing, none of the other iiow passageways in the pump housing being affected.

The next positional adjustment of the portbody, as depicted in FIG. 8, brings the pump discharge passageway directly into fiow connection with opening 97 leading to the passageway 93 connected with the filter, leaving the other passageway 91 to the filter open for flow connection to opening 109 leading to the passageway 101 from the housing.

The final permissible adjustment of the port body, illustrated in FIG. 9 connects the pump discharge passageway to the first passageway 91 leading to the lter, the other passageway to the filter being open for direct fiow connection to the discharge passageway 101 via the opening 109.

The initial and final adjustment position of the port body as depicted in FIG. 5 and FIG. 9, may be xed by abutment of a suitable stop 167 located on the port body, with a boss or cooperating stop 169. depending from the cover in the path of travel of the first stop.

To facilitate the making of the many described adjustments of the Valve assembly, a handle is provided at the exposed end of the port body shaft 127, such handle constituting a lever having a domed end 177 with depending spaced fulcrum cam lugs 179 adapted to straddle the exposed end of the port body shaft 127 and be pivoted thereto by a pivot pin through the shaft and fulcrum lugs. The handle with the fulerum cam lugs in engagement with the upper side of the cover, enable the port body 123 to be lifted from its sealing engagement with the sealing layer 118 in preparation for rotating the same by a swing of the handle. If desired, a readily replaceable wear plate 181 may be disposed about the shaft 127 along the path of movement of the' fulcrum lugs, to avoid wear on the upper surface of the cover proper.

By thus lifting the port body from its sealing engagement with the sealing layer, frictional drag at this point is eliminated completely during adjustments of the port body Within the valve assembly housing.

To guide an operator in the making of such adjustments, the valve assembly cover is provided with a circular rib 185 surrounding the shaft 127, and such rib is provided with adjustment determining notches 187, 189, 191 etc. For cooperation with such notches in locating the adjustable positions of the port body, the handle is cast with an integral pointer 197 overlying the rib and including a depending positioning rib 199, such rib being adapted to move along the upper edge of the circular rib so long as the handle is depressed to lift the port body from its seat against the sealing material.

By releasing the handle, the positioning rib may be caused to enter one of the notches to set the adjustment of the valve assembly at the position determined by the operator. To facilitate such determination, suitable symbols may be cast integral with the cover at appropriate points thereon, or otherwise applied.

In lifting the port body, preliminary to making an adjustment, liquid will gain access to that portion of the housing between the port body and the cover, and in the absence of provision to remove the same, such liquid will become trapped therein upon release of the handle. This trapped liquid in the absence of its removal, could constitute an obstacle to lifting of the valve body for subsequent adjustments.

To bring about removal of such trapped liquid from the space behind the port body, a small bleed hole Elli is provided in the upper wall of the port body, preferably in communication with the arcuate passageway as it will be noted that regardless of the adjustment of the port body in the valve assembly, this passageway is always in communication with one of the two passageways directed out of the pump housing away from the ilter. Between adjustments of the port body, suticient of the trapped liquid will drain out to permit of the necessary lifting of the valve to eliect such adjustments.

ln applying the ilter system of the present invention for use with a pool, the pump-valve unit assembly is lirst assembled to the tank assembly by cap screws 265, with a suitable gasket between the upper end of the tank pipe 19 and the lower end of the passageway 93.

A pipe connection 209 from the drain of the swimming pool is coupled to the pump housing at the inlet opening 47. A return pipe connection 2li to the pool is coupled to the pump housing at the threaded opening 167 constituting the discharge end of the passageway MP3, while a pipe connection 213 from the threaded opening 1535 leads to a waste drain or sewage system.

With the connection thus made, the position of the valve assembly as depicted in FIG. 5 will serve to block the intake passageway to the pump and the pool is thereby effectively disconnected.

The adjustable position of the valve assembly as depicted in FIG. 6 determines normal filtering operation of the ilter system, wherein the water drawn from the pool is circulated through the filter and into the return line back to the pool. In this connection, the dispersion of the water from the dispersion nozzle 99 into the iilter tank, minimizes disturbance of the tilter material therein.

The adjustment illustrated in FG. 8 determines the backwash operation of the filter system whereby sediment which may have accumulated in the filter over a period of time, is washed out of the ltcr and into the pipe 213 leading to a waste drain or sewer.

In the valve position of FG. 7, the pump discharge is connected directly to the sewer, thus bypassing the iilter, and this adjustment can be utilized when it is desired to lower the level or completely drain the pool.

In the inal positional adjustments of the valve assembly as depicted in FIG. 9, the pump discharge is directed through the tilter and then through the waste line to the sewer. This position is utilized to flush the system after backwash so that any sediment which may have filtered out in the bottom of the tank during backwash, will not be carried back into the pool but will be discharged to waste.

This same positional adjustment of the valve assembly may be used in the cleaning of the lilter sand and gravel prior to putting the filter into operational use.

To judge the completion of a cleaning operation as when the valve assembly is set to the backwash adjustment or" FIG. 8 or the adjustment of FIG. 9, a sight glass or bubble 217 is installed in the exposed wall of the passageway lol to the waste line connection.

By coupling a pressure gauge 221 and 2:23 to each of the passages 91, 93 respectively connecting with the filter, the water pressure at both the top and the bottom of the tilter tank can then be measured. Such information can be useful in determining the condition of the iilten since the diierence in pressures is an indication of the dirtiness of the iilter and the need for backwashing the same to clean out the accumulation of sediment therefrom.

The lilter system assembly of the present invention permits in a very simplified manner, of enlarging the capacity of the system through the addition thereto of supplemental tank assemblies 1, two additional such tank assemblies being depicted in FIG. 11. This is made possible through the provision of a manhole cover 227 for each tank 7, the cover including a pair of preferably integrally cast elbows 229, the lower end of one of which dll is internally threaded to receive a diituser nozzle similar to the nozzle 99 previously herein described. Each of the passageways 9i. and 93 o the pump-valve unit assembly is Ithen drilled and tapped to receive a T fitting 23S which permits of a pipe connection 237 and 239 to the corresponding passageway in the manhole cover in each ot the two additional tank assemblies. In one of the pipe connections to each of such tank assemblies, is included a control valve 241 enabling one to close oi the connection to each of such tanks. When so connected and valves 21 l open, the three tank assemblies function simultaneously as a multiple unit in filtering water drawn from the pool.

ln backwashing the filter tank assemblies of the multiple unit, it is desirable that each tank assembly be backwashed individually and to the exclusion of the others, and with this in mind, a manually operable control valve 245, preferably in the form of a butterfly valve, is installed in one of the `passages or the pump-valve assembly at a point below the T fitting connection thereto. With such valve installed and in its closed condition, the associated rilter tank assembly is cut out of the system, leaving the two end tanks still coupled, but either of these may be disconnected from the system by closing the control valve in the line leading to such tank assembly. ln other words, by closing any two of the aforementioned three valves, the tank controlled -by the remaining valve will remain open to the pump in the system, and by adjusting the valve assembly il to the backwash position, such ilter tank will be backwashed. When this particular tank has been cleaned, as determined by watching the sight glass Zll, its associated control valve may be closed, and one of the other valves .may be opened to carry out a backwa'sh operation on the ilter tank associated therewith.

By providing the pump-valve unit assembly 5 of the character described and adapted for association with a filter tank assembly l of the type described, it becomes readily apparent that the installation of a lter system, whether of the single tank type or multiple unit type, involves a minimum ot labor and materials, since the number of pipe connections and quantity of pipe required have been considerably reduced.

Aside from such savings in labor and materials, an exceedingly important additional advantage arising hom the present invention relates to the matter of shipping and transportation. Previously, the components ot the system such as the pump :and valves were mounted as individual units on the tank, and the maze of piping entailed in coupling these various units to one another and to the tank, dictated that the complete assembly be accomplished at the factory. in preparing the same for shipment therefor, the packing and crating required was considerable and costly.

When constructed in accordance with the present invention, the pump-valve lassembly unit is not only compact and relatively small in size, but by its very nature is not very susceptible to damage in handling.

The filter tank assembly oliers the advantage that it involves nothing particularly complex in its manufacture, and can readily be fabricated in the geographical location of its intended installation. Accordingly it can be readily obtainable by `a distributor without incurring the transportation costs which would be involved in having such tank assemblies shipped to him from the factory in conjunction with the pump-tank assembly.

Accordingly, the manufacturer need only shipl the pump-valve unit assembly, and thish, because of its rugged construction, need not be crated, but may be shipped in a carton of the corrugated type, designed for such purpose, thus eliminating the costs of crating in addition to reducing the shipping costs to the extent of the weight of such crating.

From the foregoing description of my invention in its preferred form, it will be apparent that the same =fullills "all the objects attributed thereto, and while` I have illustrated and described the same in its preferred form, Vit

-will be apparent that the invention is subject to alteraution land modification Without department from the underfirst and second tank assembly each including a tank haying a manhole type opening therein, each tank having a false bottom adapted to support filter material while permittin'gliquid lioW thereby, and each tank having a pipefin said `tankextending from a point below said false bottom to a point in proximity to the manhole type opening in saidV tank and supported therein, and filter material in each said tank; a single pump-valve unit assembly supported on said first tank across said opening to form with said first tank assembly a filter system assembly; said pump-'valve unit assembly having a first passageway to introduce liquid to be filtered, into the filter system assembly, a second passageway to discharge iiltered liquid out oftsaid filter system assembly, and a third passageway Vto discharge backwash waste water out of saidfilter System assembly; means coupling said second tank assembly to said pump-valve unit assembly in parallel flow con- 'nection to `said first tank assembly for simultaneous cooperation with said pump-valve unit assembly in' filt ring 'liquid entering said pump-valve unit assembly; and Vmeans for selectively disconnecting either of said'tank assemblies fromsaid system assembly to enable back Washing of each tank assembly independentlyof the'other. t i

2. A filter Vsystem assembly construction comprising, a tank assembly including a tank having a single manhole type opening in the upper end thereof, a false bottom adapted to support filter material while permitting liquid flow thereby, and a pipe in said tank extending from a V*point below said false bottom to a Vpoint in proximity to the upper end of said tank and supported therein, and

filter material in said tank; and a pump-valve unit assembly supported on said tank to close said manhole open- Y ing, saidrpump-valve unit assembly inciuding a single piece structure, said single piece structure havingiiange meansV cooperating with the peripheral opening forming Vportion of said tank to span said manhole, opening, a

pump chamber in said single piece structure, a passageway leading to said pump chamber for intake of liquid and a passageway leading therefrom for discharge of 0 over the terminal ropenings in saidV aforementioned wall Y from a point below saidjfalse bottom to a pointfin proximity to the upper end of said tank and welded to said false bottom, and a plurality of layers of filter material in said tank; and a pump valve unit assembly supported on said tank to close said manhole opening, said pump valve unit'assembly including. asingle piece structure, said single piece structure having ange means cooperating with'the peripheral opening forming portion of said tank to span said manhole opening, a pump chamber in said single piece structure, a passageway leading to said pump chamber for intake of liquid and a passageway leading therefrom to an opening in a wall of said single vpiece structure, a pair ofrpassageways extending completely through said single piece structure independent of said pump chamber and its associated intake and dis-V charge passageways, each of said Vindependent passageways terminating at one end in an opening in they bottom Y of said single piece structure and at its other end in an opening in saidforementioned Wall, andan additional pair of passageways extending throughsaid single piece structure also independent of said pump chamber and its associated intake and discharge passageways, each of said additionalpair of passageways terminating-at' one end in Van opening in said aforementioned Wall of said single piece structure and at its other end in a different wall of said'rsingle piece structure, the passageways terminalV openings in said aforementioned Wall lying in a circle, Vsaid pump valve unit' assembly also comprising a multiway Valve assembly aflixed to said single piece structure and adapted to selectively intercouple Vsaid terminal openings in desired combinations, a diffuzer nozzle extending fromrsaid single piece structure at the lower `terminal opening of Yone of said first pair of passageways and through said tank opening, pump means insaid pump chamber, and meansv for effecting flow connections through said ltank opening between the Vlower end of the liquid, and a pair of passageways independent of said pumpchamber and its associated intake andrpdischarge passageways `extending completely through said single piece structure with each of saidrindependent passageways Y terminating at one end in an opening in the bottom of said single piece structure and exposed to the interior of said filter tank, said single structure having an additional pair of passageways for separately discharging filtered liquid and waste from said filter system assembly, said 'pump-valve unit assembly also including pump means in ,said pump chamber, means for effecting a flow connection between said discharge passagewayV and the other end of of one of Vsaid pair of passageways, a diffuser nozzle extending from said Vsingle piece structure at the lower terminal opening of said last-mentioned passageway and through saidV tank opening, and means for effecting flow connection-through said tankopening between the lower endV of the other of said pair of passageways of said single piece structure and said tank pipe when said pump valve unit assembly is installed on said tank.

. 3. A filter system assembly construction comprising, Y' a tank assembly including a tankrhaving a single manhole type opening in the upper end thereof, aY convex perfo-1 `rated false bottom adapted to support filter material While permitting flow thereby, and a pipe in said tank extending other of said first pair of passageways of said single piece structure and rsaid tank pipe when said pump valve unit assembly is installed on said tank.

l 4. A' pump-valve unit assembly' construction for a yswimming pool system, including' apool, a filter, and a waste drain, comprising a single piece structure; said single piece structure including a mounting ilange at the bottom thereof for cooperatingy with a filter tankrhaving a single manhole type opening to close said tankV opening, i

a pump chamber in said single piece structure, a passageway leading to said pump chamber for intake of liquid from such pool and a passageway leading therefrom to an opening inthe top wall of said singlefpiece structure, Va Vpair of passageways extending through said single piece structure independent of said pump chamber and its associated intake and discharge passageways; each of said independent passageways'tterminating at one end in an Y opening in the bottom of said single piece structure and lat itsiother end in an opening in'sad top wall, andV anV additional pair of passagewaysthrough said single piece structure also independent'of said pump chamber and its associated intake and discharge passageways, one of said additional pairof passageways' being adapted for connection to such pool and the other to such Waste drain,'with each of said *additionalV pair of passageways terminating Y at one end in an opening in Vsaid top'Wall of Vsaidfsingle piece structure and at its other end at a different Wall of said single piece structure, the passageways terminal openings Yin said top wall lying in a circle; pump means in said pump chamber; a multi-Way valve assembly affixed to said singlepiece structure over the circularly arranged terminal openings in said aforementioned top Wall and adaptedtin one position, to' couple said pump discharge through such'flr ,to'such pool, and in another position to reverse liowfthroughsuch filter and Vdisc'hargeto waste.

[References oni following page) Refeaences Cited by the Examiner 2,570,258 UNHED STATES PATENTS 25752923 2,780,998 5/89 DZWIS 210--263 2 790 461 ThUIStOD. 9/10 301165 10S-2 X 5 2,961,968 6/ 17 McCaslin 103-2 X 2/ 19 Riedler 103-2 X 12/35 Cocks et al 210-258 X 10/42 Eickmeyer et a1. 210--278 X 11/48 Brseh et al 210-253 10 1@ McGi et al 210--278 X McMahan et al. 103-2 X Clker H13-106 Lightfoot et a1. 210-169 Culver Q10-169 Thomas et a1. 10B-106 REUBEN FREDMAN, Primary Examiner.

HERBERT L. MARTIN, ROBERT M. WALKER,

HARRY B. THORNTON, Examiners. 

1. A FILTER SYSTEM ASSEMBLY CONSTRUCTION COMPRISING, A FIRST AND SECOND TANK ASSEMBLY EACH INCLUDING A TANK HAVING A MANHOLE TYPE OPENING THEREIN, EACH TANK HAVING A FALSE BOTTOM ADAPTED TO SUPPORT FILTER MATERIAL WHILE PERMITTING LIQUID FLOW THEREBY, AND EACH TANK HAVING A PIPE IN SAID TANK EXTENDING FROM A POINT BELOW SAID FALSE BOTTOM TO A POINT IN PROXIMITY TO THE MANHOLE TYPE OPENING IN SAID TANK AND SUPPORTED THEREIN, AND FILTER MATERIAL IN EACH SAID TANK; A SINGLE PUMP-VALVE UNIT ASSEMBLY SUPPORTED ON SAID FIRST TANK ACROSS SAID OPENING TO FORM WITH SAID FIRST TANK ASSEMBLY A FILTER SYSTEM ASSEMBLY; SAID PUMP-VALVE UNIT ASSEMBLY HAVING A FIRST PASSAGEWAY TO INTRODUCE LIQUID TO BE FILTERED, INTO THE FILTER SYSTEM ASSEMBLY A SECOND PASSAGEWAY TO DISCHARGE FILTERED LIQUID OUT OF SAID FILTER SYSTEM ASSEMBLY, AND A THIRD PASSAGEWAY TO DISCHARGE BACKWASH WASTE WATER OUT OF SAID FILTER SYSTEM ASSEMBLY; MEANS COUPLING SAID SECOND TANK ASSEMBLY TO SAID PUMP-VALVE UNIT ASSEMBLY IN PARALLEL FLOW CONNECTION TO SAID FIRST TANK ASSEMBLY FOR SIMULTANEOUS COOPERATION WITH SAID PUMP-VALVE UNIT ASSEMBLY IN FILTERING LIQUID ENTERING SAID PUMP-VALVE ASSEMBLY; AND MEANS FOR SELECTIVELY DISCONNECTING EITHER OF SAID TANK ASSEMBLIES FROM SAID SYSTEM ASSEMBLY TO ENABLE BACK WASHING OF EACH TANK ASSEMBLY INDEPENDENTLY OF THE OTHER. 